In the conventional hard-bound cover book binding process, the outside cover is called the "case". It is ordinarily formed of two pieces of rigid chip board, glued to a covering material with a separation between them, called the spine, equal in width to the approximate thickness of the book that is to be bound within the covers. The basic group of pages of a case-bound book are collectively referred to as a "signature". Each of the signatures to be bound in the book are typically stitched to a fabric inner spine which holds the signatures together and forms the signatures into a book-like structure. All of the pages to be bound in a book are collectively called the "book block" or the "insides", and may include one or more signatures or may be formed of individual page-sized sheets. The stitched book block is then attached to the case by "end papers" or fly leaves which are, in turn, formed of a sheet of paper folded in half so that the folded size, now two pages, is approximately equal to the size of one page of the book block.
One half of each of the end leaves is glued to one of the inside covers of the case (from and back covers), and the other half of the end leaves is glued to the first page of the book block and the last page of the book block, forming a two page fly leaf. The end result is two single sheets of paper folded in half, one glued to the inside of the from cover of the case and to the first page of the book block and the other glued to the inside of the back cover of the case and to the last page of the book block. This technique is the standard for high quality commercial production of all types of hard bound, generally high-quality, books.
One of the difficulties with the traditional processes necessary to achieve the high-quality look of case-bound or other hard-bound bindings for books is that the stitching and assembly of the parts of the product require large and very expensive specialized equipment operating in large specially-designed facilities and operated by highly skilled technicians. It is virtually impossible to carry out the traditional case-bound binding process in a small office and on a small scale. Binding equipment and systems have recently become available for the production of small quantities of catalogs, brochures and other reports in a typical office environment. This special aspect of book binding technology is herein called "desktop binding". The term "desktop binding" is used as a term of art to describe a binding operation adapted to be carded out in an office environment (as opposed to a commercial bindery environment). The "desktop binding" operation involves binding less than commercial quantities of books, and involves binding individual sheets of paper rather than folded, multi-leaf folios. It typically seeks speed, convenience, low-capital investment and quality over volume and cost efficiency. The system usually is based on a pre-formed flexible binder cover with a strip of hot-melt adhesive on the inside spine. The pages to be bound are placed with their edge against the hot melt adhesive and the binder spine is placed in a special piece of equipment which heats up the hot melt equipment and causes the sheets to be bound into the cover. The fact that the pages and cover are frequently bound together at the spine in a somewhat inflexible manner is acceptable because the covers themselves are quite flexible.
More specifically, the products available on the market have cases made from either one piece of material with creases to create the hinge and a strip of hot-melt adhesive layered in place on the inside of the spine between the hinges of the cover or creases. Some covers (cases) may have three pieces of chip board covered with a binding material, with space between the spine and each of the front and back covers to create a hinge. The inside of this cover would be lined with a plain type of paper which would hide the edges of the covered material as it was turned over the edge of the clipboard stiffener, and, in effect, this approach would duplicate the appearance of the typical commercial case-made book. This cover would also have a strip or ribbon of hot-melt adhesive applied to the spine between the creases or hinges. Such a case is shown in perspective in FIG. 1. Such a product would have a front cover 12, a rear cover 13, and a spine 14. A liner 21 would be adhesively bound to the inside of the front cover 12 and the inside of the rear cover 13 and extend across the spine groove 15 to form a bridge across the spine groove 15. 0n the inside surface of this bridge 20 would be a layer of hot-melt adhesive 30. Liner 21 could be replaced by a tape which forms the bridge.
A diagrammatic view of the hot-melt binding method is shown in FIG. 2. The book block 11 of pages is placed in the case 10 with the edge of the book block abutting the adhesive strip 16 which is adjacent the spine 14. The resulting combination is placed in the binding equipment 31 which is made up of a clamping assembly 32 including an anvil 33 and a clamp 34, and a heating element 35. Once the unbound assembly is placed in the clamping assembly, the heating element melts the adhesive and binds the pages into the case.
FIG. 3 shows an end view of the spine of the prior art construction. The case 10 has the front cover 12, the rear cover 13, and the spine 14. The liner 21 is adhesively bonded to the covers by adhesive layers 16. The liner 21 bridges across the spine 14, to form an open-ended spine groove 15 or tunnel., and carries, on its inner surface, the hot-melt adhesive 30.
In FIG. 4, the case is shown with the book block 11 standing on the adhesive 30.
In FIG. 5, the case is shown with the front cover 12 and the rear cover 13 folded up against the book block.
In FIG. 6, the hot-melt adhesive is shown after the melting process has been carried out. It can be seen that excess adhesive has expressed outwardly from the ends of the hot-melt strip 30 and has been carried upward between the first page of the book block 11 and the liner 21, on one side, and the last page of the book block 11 and the liner 12, on the other side.
In FIG. 7 it can been seen that when the rigid front cover 12 and rear cover 13 are folded downward in the open-book position, the excess adhesive must either undesireably bond the first (and last) page and the liner together so that the cover cannot lie flat, or, eventually, must separate from one or the other of the surfaces to which the excess adhesive has become fixed. The result is that either a page of the book block is torn as shown as element 23 or the liner 21 is torn as shown as 24. In either case, the result is an unsightly and therefore unacceptable binding product which does not provide the high quality appearance which is necessary in order for the case-bound process to be effectively carried out in a hot-melt technology.
These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is therefore, an outstanding object of the invention to provide a case-bound binding system which can be carried out in a typical office environment.
Another object of the invention is the provision of a case-bound binding process in which the excess hot-melt adhesive does not create unsightly destruction of the parts of the product nor does it inappropriately limit the range of motion (especially, the ability to lie fiat) of the product.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.